Process for decolorizing petroleum resins and products obtained by adding the decolorized resins to fuel oil



PROCESS FOR DECOLORIZING PETROLEUM RES- INS AND PRODUCTS OBTAINED BY ADDING THE DECOLORIZED RESINS TO FUEL OIL Charles N. Hudson, Springdale, Conn., assignor to Sinclair Refining Company, New York, N.Y., a corporation of Maine NoDrawing. Filed July 23, 1957, Ser. No. 673,576

6 Claims. (Cl. 208-15) This invention relates to the decolorization of hydrocarbon oil additives and more particularly to the hydrodecolorization of resinous petroleum fractions useful, for instance, in hydrocarbon fuel oils as a pour point depressant.

Many petroleum stocks which could be considered suitable for diesel and heating fuels are limited in utility by the inability to meet certain specifications, for example, as to pour point. That is, these stocks do not pour readily at the low temperatures frequently encountered due to place or time of use. The high pour points that characterize these fuels may be substantially reduced to meet pour point specifications by incorporating into the heating fuels a small amount of a propane-insoluble heavy petroleum resin. However, use of the resinous ad'- ditive as a pour depressor in the production of fuel oil distillates has been found to present undesirable off-color finished fuels. Attempts have been made to eliminate the objectionable color of the resin-containing finished fuels by subjecting the raw petroleum resin to hydrodecolorization operations prior to its incorporation into the fuel oil distillate. These attempts have proved unsuccessful in that during the hydrode'colorization operation the pour depressor properties of the petroleum resin are invariably destroyed.

I have now found that the oil-soluble propane-insoluble petroleum resins prepared for use as fuel pour depressors can be successfully hydrodecolorized without loss of depressor properties by sufficiently diluting the resinous depressor with fuel oil stock prior to hydrogen treatment.

The petroleum resin additive hydrodecolorized'in my invention is obtained as a propane-insoluble fraction from the propane treatment of reduced crude or bottoms fraction from a Pennsylvania or paraffin base crude oil. The resins have viscosities of about 3000 to 10,000 SSU at 210 F. As the viscosity increases, their tendency to precipitate from the propane solution increases and advantage is taken of this fact to effect a fractionation of the wide range resin and obtain any desired resin fraction, the preferred fraction having a viscosity of about 5000 to 8000 SSU at 210 F. Similar fractions having the desired properties can be obtained by distillation of Pennsylvania reduced crudes.

In carrying out my invention about 0.05 percent to 2 percent, preferably about .30 to 1.0 percent of the petroleum resin additive is incorporated into petroleum fuel oil stocks characterized by boiling in a range of about 300 to 900 F., preferably about 350 to 700 F., and the blend subjected to hydrodesulfurization processing. The hydrodesulfurized products can then be used as such, for instance as fuel, or incorporated into an additional amount of a petroleum hydrocarbon fuel oil boiling in States Patent "ice the range of about 300 to 900 F., preferably about 300 to 750 F. to provide a pour depressed fuel oil of acceptable color containing from about 0.01 to 1.5 percent, preferably about 0.01 to 0.15 percent, of the pour depressor resin.

The petroleum fuel stocks with which the defined resinous depressor may be diluted prior to hydrodesulfurization are mineral oil fractions of the indicated boiling range and known in the art, for instance, as heavy and light catalytically cracked distallates, thermally cracked distillates, such as coker gas oils, other cycle oils from the coking of residuums or heavy stock, straight run stocks, or mixtures of the straight run stocks with any of the above cracked components. Frequently, the distillate fuel materials employed comprise about 15 to 100 percent cracked distillate with substantially the balance being straight run stock and are characterized by pour points of at least about 5 F.

Base fuel materials which can be modified by the addition of the hydrodecolorized products of my invention to effect pour point lowering are characterized by boiling ranges of about 300 to 900 F. Typical materials are any of the cracked distillate fuel materials or blends thereof described above as possible diluent stocks for the defined resinous pour depressor. These stocks can be blended with straight run distillate fuels boiling within about 300 to 675 F. to improve the sulfur content, volatility and percentage carbon residue. This blending may result in slightly improved pour point also, but usually the improvement obtained is insufficient to meet specifications. Substantial amounts, i.e. up to about 10 percent of high boiling, high pour point marginal stocks, such as paraffin tower overhead, may also be included. Base compositions thus comprise about 15 to 100 percent of cracked distillate and substantially the balance straight run stock and usually are characterized by pour points of at least about 5 F., cetane numbers of about 25 to 50, boiling ranges within about 300 to 900 F., and have percent points of at least about 600 F. and preferably at least about 700 F.' The preferred diesel fuel base material is about a 50/50 blend of heavy and light catalytically cracked distillates.

The hydrodesulfurization operation of my invention should be conducted underconditions'that are unlikely to produce substantial cracking of the fuel oil diluenta pour depressor composition. Employment of hydrodesulfurization conditions effecting substantial cracking has been found to destroy the pour depressor properties of the resin and should for that reasonibe avoided. Suitable processing conditions atfording a product of acceptable color level are in the following approximate ranges:

ably 650-700 F. Weigl1t of hydrocarbon per weight of catalyst per hour.

Any suitable desulfurization or decolorization catalyst can be employed, for instance, a calcined or activated catalyst containing minor amounts of cobalt and molybdena or cobalt molybdate supported on alumina.

The following examples are presented in order to further illustrate my invention. The physical properties of the heavy petroleum resin and cracked fuel oil distillates employed in the examples are indicated in Table I.

TABLE I TABLE III Tests on stocks 'r t r 1011131 dN 1 TestNo' es s on he on o. Fluid Catalytic Pennsylvania Cycle 011 Heavy Resin 1 2 3 4 vity. PI 23.6w 70 so Blend No. 111 drodesulfurlza Flash, F 215 (PM)-- 680 (C). i tlon Product: I y

740. Color, NPA 4 2% 2 Cloud Point, F-.. 6 8 8 2 Viscosity at 210 F. 774 10 Poor Point, F 13-30 13-30 13-5 B-30 Cloud Point, F 70/30 Blend N o. l/Feed to Hydro- P0111 Point, F 15 desulfurization Unit: Color 2% (NPA)---- 0 Color, NPA 4% 6 6 8 Carbon Resldue, Perccn 12.76. Cloud Point, F.. 8 4 4 T00 golfing Percent.-- Nu 0.31.8 Dark s 1, ercent 0.25 P Po t, F 13-30 B-30 B- B- Distillation (200 ml.) IBP, F 440 15 our m 30 3O EXAMPLE I To a fluid light cycle fuel oil having the physical properties shown in Table I were added various amounts of a Pennsylvania heavy resin whose physical properties are also shown in Table I.

A 50 gram portion of a calcined cobalt-molybdena on alumina desulfurization catalyst typically analyzing 25% Co, 9.0% M00 was charged to a one inch reactor as a solid bed, with A1 Alundum balls filling the entire space above the catalyst. The reactor was pressure tested and placed in a furnace. The catalyst was purged with hydrogen for 2 hours at 680 F., and 1 atmosphere, after which the reactor was pressured and the entire system pressure tested. Hydrogen gas recycle flow was started and the light cycle oil-resinous additive feed cut in. Process conditions and test results on the charge to the hydrodesulfurization unit and the tests on the hydrodesulfurized products are shown in Table II.

TABLE II Test No. Process Conditions Feed Percent Penn. Heavy Resin 0.33 .66 .66 1.0 Fl id Light Cycle Oil 99.67 99. 84 99. 34 99. 0

Temperature, F Press-re, P.s.i.g.-

Comparison of tests 1 through 4 on the hydrodesulfurized products to those on the feeds to the unit shows that a substantial reduction of both sulfur and color was effected by the various process conditions. The sulfur removal indicates no apparent loss of desulfurization activity during the course of the tests. Although all percentages of Pennsylvania heavy resin to light cycle oil afiorded a product of lighter color, the most favorable rcsults are produced when about 0.5 to 0.75, e.g. 0.66, percent by weight of the resin is incorporated in the cycle oil. The adding of this amount of heavy resin elfects a more desirable NPA color of below 4 to 5 when operating within the process conditions of this invention. If any dark colored hydrodesulfurized products should result under a particular set of operating conditions wherein the resin is employed, it may be remedied by simply adjusting the conditions of space velocity and/or temperature to increase the severity while avoiding cracking.

The hydrodesulfurized products of tests 1 to 4 were added to heating oil to produce a fuel blend composed of 70 percent heating oil and 30 percent hydrodesulfurized products. Tests on these fuel oil blends arereported in Table III.

Tests:

Color N PA Cloid Point, F Pour Point, F

B=below.

As shown, addition of the undesulfurized heavy resinlight cycle oil blend reduced the pour point of fuel blend No. 1 from 5 F. to below 30 F. but resulted in products in tests 2, 3 and 4 that are too dark (NPA 6 and 8) for ready acceptance. On the other hand, incorporation of the hydrodesulfurized products obtained under the process conditions of the tests in Table II into fuel blend No. 1 gave a fuel of reduced pour point and of lighter color. The color reductions (NPAcolor of 2 /2 and 2) were obtained with the hydrodesulfurization product afforded under the conditions of tests 2 and 3 in Table II, wherein .66 percent of the resin was present in the oil desulfurized; however, the more severe conditions in test 3 gave some loss of pour point depressor properties. Preferably, the decolorizing conditions should not be so severe that more than 10 F. of pour depressing properties are lost.

I claim:

1. A process for the decolorization of an oil-soluble, propane-insoluble, parafiin base-derived resinous petroleum fraction having a viscosity of about 3,000 to 10,000 SSU at 210 F. for use as a pour depressor in petroleum hydrocarbon stocks, which comprises contacting a blend consisting essentially of about 0.05 to 2.0 percent by weight of said resinous petroleum fraction and a petroleum fuel oil stock boiling in the range of about 300 to 900 F. with a desulfurization catalyst under non-cracking conditions of approximately 600 to 780 F., 0.5 to 4.0 WHSV, 300 to 1000 p.s.i. and 3 to 20 to 1 hydrogen to fuel oil stock ratio.

2. A process for the decolorization of an oil-soluble, propane-insoluble, parafiin base-derived resinous petroleum fraction having a viscosity of about 5000 to 8000 SSU at 210 F. for use as a pour depressor in petroleum hydrocarbon stocks, which comprises contacting a blend consisting essentially of about 0.3 to 1.0 percent by weight of said resinous petroleum fraction and a petrolem fuel oil stock boiling in the range of about 350 to 700 F. containing cracked components with a desulfurization catalyst under non-cracking conditions of approximately 650700 R, 0.5-4.0 WHSV, 300 to 1000 p.s.i. and 5 to 10 hydrogen to fuel oil stock ratio.

3. A decolorized, pour depressed composition prepared by a process which comprises contacting a blend consisting essentially of about .05 to 2 percent by weight of an oil-soluble, propane-insoluble, paratlin base-derived resinous petroleum fraction having a viscosity of about 3,000 to 10,000 SSU at 210 F. and a petroleum fuel oil stock boiling in the range of about 300-900" F. with a desulfurization catalyst under non-cracking conditions of approximately 600-780 F., 0.5 to 4.0 WHSV, 300 to 1000 psi. and 3 to 20 to 1 hydrogen to petroleum fuel oil stock ratio.

4. A pour depressed fuel oil composition consisting essentially of a petroleum hydrocarbon fuel oil boiling ficient of the product of claim 2 to provide about 0.01 in the range of about 300 to 900 F. and containing at to 0.15 percent of the petroleum resin.

least about 15 percent of cracked components and sufficient of the product of claim 1 to provide about 0.01

t 2,0 percent f h petroleum resin 5 References Cited in the file of this patent 5. A pour depressed fuel oil composition consisting essentially of a petroleum hydrocarbon fuel oil boiling UNITED STATES PATENTS in the range of about 300 to 900 F. and containing at 2,143,882 Keith et a1. J an. 17, 1939 least about 15 percent of cracked components and suf- 2,204,967 Moser June 18, 1940 ficient of the product of claim 2 to provide about 0.01 to 10 2,323,360 Wallace July 6, 1943 2.0 percent of the petroleum resin. 2,339,898 White et al. Jan. 25, 1944 6. A pour depressed fuel oil composition consisting 2,756,183 Knox July 24, 1956 essentially of a petroleum hydrocarbon fuel oil boiling 2,773,004 Martin Dec. 4, 1956 in the range of about 300 to 750 F. and containing at 2,793,986 Lanning May 28, 1957 least about 15 percent of cracked components and suf- 15 2,799,661 De Rosset July 16, 1957 

3. A DECOLORIZED, POUR DEPRESSED COMPOSITION PREPARED BY A PROCESS WHICH COMPRISES CONTACTING A BLEND CONSISTING ESSENTIALLY OF ABOUT .05 TO 2 PERCENT BY WEIGHT OF AN OIL-SOLUBLE, PROPANE-INSOLUBLE, PARAFFIN BASE-DERIVED RESINOUS PETROLEUM FRACTION HAVING A VISCOSITY OF ABOUT 3,000 TO 10,000 SSU AT 210*F. AND A PETROLEUM FUEL OIL STOCK BOILING IN THE RANGE OF ABOUT 300-900*F. WITH A DESULFURIZATION CATALYST UNDER NON-CRACKING CONDITIONS OF APPROXIMATELY 600-780*F., 0.5 TO 4.0 WHSV, 300 TO 1000 P.S.I. AND 3 TO 20 TO 1 HYDROGEN TO PETROLEUM FUEL OIL STOCK RATIO. 